EP 0 403 635 B1 discloses a combined brake caliper of this type for use in a motor vehicle disc brake. The brake caliper comprises a housing with a bore, in which a piston is arranged in a displaceable fashion for brake application. A shaft is pivoted in the brake housing for parking brake operations, and the shaft extends through the brake housing and is connected to a ramp element of a ramp arrangement. A second associated ramp element is arranged formed fast with the housing.
Due to the connection of shaft and ramp arrangement, the shaft will perform a rotation and an axial displacement when the parking brake is operated. The shaft transmits the axial displacement to a spindle of a readjusting device, and an axial bearing is interposed between the shaft and the spindle in order to uncouple the translation from the rotation. The axial displacement is transmitted to the piston by way of the readjusting device. To convert the rotation into an axial movement, the spindle of the readjusting device must be supported in tangential direction in the housing using a cartridge of the readjusting device. This anti-rotation safeguard is required because the axial bearing transmits a residual torque into the spindle.
In this arrangement, the cartridge is unrotatably coupled to the ramp arrangement on the housing and includes three longitudinal slots, in which the spindle is supported tangentially by means of three projections. It is disadvantageous in this respect that considerable surface pressures and tension peaks occur at the edges of the slots and at the projections of the spindle, and that this uneven component stress leads to an increase in wear. The longitudinal slots cause low stability of the cartridge, thus necessitating a major wall thickness of the cartridge.
To relieve the components of the anti-rotation safeguard from stress, it is disclosed to design the axial bearing between shaft and spindle as a rolling or slide bearing. The use of a rolling bearing allows achieving introduction of low torque into the anti-rotation safeguard. Since rolling bearings are cost-intensive, increase the complexity of components and require hardening of the respective sliding surfaces, this solution entails high costs of manufacture and is, therefore, considered not practicable. Compared thereto, a slide bearing with an axially active slide bearing plate brings about cost benefit, yet causes increased component tension in the readjusting device due to the higher bearing friction. Based on the above, it is desirable to have a generic brake caliper of a disc brake, with the components having a construction to withstand stress so that they are exposed to even, low stress without detrimental tension peaks.